Loving your work Fietsbob :0)

On cadence 90rpm is a reasonable pace and the most efficient on the flat I was told by a v experienced coach. 160rpm is doable for some and it depends on any differences in the lengths of your legs. The more symmetrical you are, the less this induces a rocking motion which destroys rhythm. Personally I can do about 130rpm, which equates to 35mph on my Chameleon and no I don't need a hill for that, just a gel :0) it would go faster if I changed the top gear and did some training. If you want to improve your cadence start riding a 700c fixie on medium gears (eg 44x17).

Theoretically a small-wheel bike sees increasing effects from bearing friction as it gets faster, in comparison to more conventional bikes. In practice any decent hill will show you this effect is outweighed by aerodynamics.

BTW Terminal Velocity is zero, when you think about it ;0)